Minor error in autogen help text for nasm

Hello,

I spotted a minor error in the autogen help text for when you have no 
nasm installed.

Bugzilla help says <https://wiki.documentfoundation.org/QA/BugReport> 
bugs connected with building LibreOffice should be reported on this 
mailing list.
Mailing list help says 
<https://wiki.documentfoundation.org/Development/Mailing_List> bugs get 
reported in Bugzilla.
So, I'm sorry if this is in the wrong place.  I'm new here - please help 
me to report this...

When I first ran autogen.sh I did not have yasm or nasm installed. I got 
a message saying "consult 
http://svn.code.sf.net/p/libjpeg-turbo/code/trunk/BUILDING.txt";. But 
that is a broken link.

I think the message may be coming from here: 
https://cgit.freedesktop.org/libreoffice/core/tree/configure.ac#n7649

I think a better URL to cite might be 
https://github.com/libjpeg-turbo/libjpeg-turbo/blob/master/BUILDING.md

For information, I'm trying to report this minor bug; I'm not asking for 
help with the build.  I have since installed yasm and have successfully 
built LibreOffice - thanks.